Single plate hydrodynamic bearing with extended single journal bearing

Abstract

A hydrodynamic bearing having a shaft relatively rotatable with rest to a surrounding sleeve and having a thrust plate of or near one end thereof. The shaft and sleeve define a journal bearing extending substantially the full length of the two relatively rotating parts.

What is claimed is:  
     
       1. A hydrodynamic bearing comprising a sleeve and a shaft fitted into an axial bore of said sleeve, said shaft and said sleeve rotating relative to each other, a surface of said shaft defining together with a surface of said sleeve a single journal bearing comprising a single group of continuous curved grooves formed on one of said surfaces of said shaft and said sleeve and extending continuously along said one surface and offset toward thrust plate so that said shaft is stiffly supported within said sleeve by a fluid in a gap between said shaft and said sleeve during relative rotation of said shaft and said sleeve; said shaft further supporting an annular thrust plate, said thrust plate extending into a recess formed by an axial face of said sleeve to form a first gap, and a counterplate parallel to said thrust plate and attached to said sleeve to form a second gap, an axial face of said thrust plate defining together with the adjacent thrust plate surface a first thrust bearing including said first gap and fluid therein, and the second gap between said thrust plate and said counterpart forming a second thrust bearing with fluid therein, and wherein grooves are defined connecting said second gap to said first gap so that said fluid bearing fully supports said shaft within said sleeve. 
     
     
       2. A hydrodynamic bearing as claimed in claim  1  wherein a diameter of said sleeve has a ratio to a length of said journal bearing of about 1:1. 
     
     
       3. A bearing as claimed in claim  1  wherein the gap between the shaft and the surrounding sleeve is 5 to 7 microns. 
     
     
       4. A hydrodynamic bearing comprising a sleeve and a shaft fitted into an axial bore of said sleeve, said shaft and said sleeve rotating relative to each other, a surface of said shaft defining together with a surface of said sleeve a single journal bearing comprising a single group of continuous curved grooves formed on one of said surfaces of said shaft and said sleeve and extending continuously along said one surface and offset toward thrust plate so that said shaft is stiffly supported within said sleeve by a fluid in a gap between said shaft and said sleeve during relative rotation of said shaft and said sleeve; said shaft further supporting an annular thrust plate, said thrust plate extending into a recess formed by an axial face of said sleeve to form a first gap, and a counterplate parallel to said thrust plate and attached to said sleeve to form a second gap, an axial face of said thrust plate defining together with the adjacent thrust plate surface a first thrust bearing including said first gap and fluid therein, and the second gap between said thrust plate and said counterpart forming a second thrust bearing with fluid therein, and wherein a first end of said journal bearing distal from said annular thrust plate terminates in a capillary seal formed between said bushing integral with said sleeve and said shaft of said motor. 
     
     
       5. A spindle as claimed in claim  4  wherein said surfaces of said sleeve is inclined away from said shaft to form said capillary seal. 
     
     
       6. A bearing as claimed in claim  5  wherein said curved grooves are generally sinusoidal. 
     
     
       7. A bearing as claimed in claim  4  wherein said curved grooves are generally sinusoidal. 
     
     
       8. A bearing as claimed in claim  1  wherein said curves grooves are generally sinusoidal. 
     
     
       9. A hydrodynamic bearing as claimed in claim  8 , wherein a diameter of said sleeve has a ratio to a length of said journal bearing of about 1:1. 
     
     
       10. A hydrodynamic bearing comprising a sleeve and a shaft fitted into an axial bore of said sleeve, said shaft and said sleeve rotating relative to each other, a surface of said shaft defining together with a surface of said sleeve a single journal bearing comprising a single group of continuous curved grooves formed on one of said surfaces of said shaft and said sleeve and extending continuously along said one surface and offset toward thrust plate so that said shaft is stiffly supported within said sleeve by a fluid in a gap between said shaft and said sleeve during relative rotation of said shaft and said sleeve; said shaft further supporting an annular thrust plate, said thrust plate extending into a recess formed by an axial face of said sleeve to form a first gap, and a counterplate parallel to said thrust plate and attached to said sleeve to form a second gap, an axial face of said thrust plate defining together with the adjacent thrust plate surface a first thrust bearing including said first gap and fluid therein, and the second gap between said thrust plate and said counterpart forming a second thrust bearing with fluid therein, and wherein a diameter of said sleeve has a ratio to a length of said journal bearing of about 1:1. 
     
     
       11. A bearing as claimed in claim  10  wherein said curved grooves are generally sinusoidal.